MapsActivity.java

package com.humble.googlemapsdemo;

import android.Manifest;
import android.content.Context;
import android.content.pm.PackageManager;
import android.location.Location;
import android.location.LocationListener;
import android.location.LocationManager;
import android.os.Build;
import android.support.annotation.NonNull;
import android.support.v4.app.ActivityCompat;
import android.support.v4.app.FragmentActivity;
import android.os.Bundle;
import android.support.v4.content.ContextCompat;
import android.util.Log;

import com.google.android.gms.maps.CameraUpdate;
import com.google.android.gms.maps.CameraUpdateFactory;
import com.google.android.gms.maps.GoogleMap;
import com.google.android.gms.maps.OnMapReadyCallback;
import com.google.android.gms.maps.SupportMapFragment;
import com.google.android.gms.maps.model.LatLng;
import com.google.android.gms.maps.model.MarkerOptions;

import static com.google.android.gms.common.GooglePlayServicesUtil.isGooglePlayServicesAvailable;

public class MapsActivity extends FragmentActivity implements OnMapReadyCallback {

    private GoogleMap mMap;
    LocationManager locationManager;
    LocationListener listener;
    @Override
    public void onRequestPermissionsResult(int requestCode, @NonNull String[] permissions, @NonNull int[] grantResults) {
        super.onRequestPermissionsResult(requestCode,permissions,grantResults);
        if(grantResults.length > 0 && grantResults[0] == PackageManager.PERMISSION_GRANTED){
            if(ContextCompat.checkSelfPermission(this,Manifest.permission.ACCESS_COARSE_LOCATION)==PackageManager.PERMISSION_GRANTED){
                locationManager.requestLocationUpdates(LocationManager.GPS_PROVIDER,0,0,listener);
            }

        }
    }
    @Override
    protected void onCreate(Bundle savedInstanceState) {
        super.onCreate(savedInstanceState);
        setContentView(R.layout.activity_maps);

        // Obtain the SupportMapFragment and get notified when the map is ready to be used.
        SupportMapFragment mapFragment = (SupportMapFragment) getSupportFragmentManager()
                .findFragmentById(R.id.map);
        mapFragment.getMapAsync(this);
    }


    /**
     * Manipulates the map once available.
     * This callback is triggered when the map is ready to be used.
     * This is where we can add markers or lines, add listeners or move the camera. In this case,
     * we just add a marker near Sydney, Australia.
     * If Google Play services is not installed on the device, the user will be prompted to install
     * it inside the SupportMapFragment. This method will only be triggered once the user has
     * installed Google Play services and returned to the app.
     */
    @Override
    public void onMapReady(GoogleMap googleMap) {
        mMap = googleMap;
        mMap.setMapType(GoogleMap.MAP_TYPE_HYBRID);
        locationManager = (LocationManager) this.getSystemService(Context.LOCATION_SERVICE);
        //Location Listner for listening to location change
        listener = new LocationListener() {
            @Override
            public void onLocationChanged(Location location) {
                double lat = location.getLatitude();
                double longitude = location.getLongitude();
                LatLng current = new LatLng(lat,longitude);
                mMap.clear();
                mMap.addMarker(new MarkerOptions().position(current).title("Your Current location"));

            }

            @Override
            public void onStatusChanged(String provider, int status, Bundle extras) {

            }

            @Override
            public void onProviderEnabled(String provider) {

            }

            @Override
            public void onProviderDisabled(String provider) {

            }
        };
        //Cheking wheather permission has been provided or not
        //In this ContextCompat provides backward compatibility to the previous versions of the android
        //PackageManager contains the string for the Permission Granted or not
        if (ContextCompat.checkSelfPermission(this,Manifest.permission.ACCESS_FINE_LOCATION)!=PackageManager.PERMISSION_GRANTED){
            //Request for the permission will not be done automatically, it has to be asked for
            //This job is done in the code below
            //Observe that the String array can be defined within the given function if it is not used anywhere else
            ActivityCompat.requestPermissions(this,new String[] {Manifest.permission.ACCESS_FINE_LOCATION},1);

        } else {
            locationManager.requestLocationUpdates(LocationManager.GPS_PROVIDER,0,0,listener);
            Location lastknownlocation = locationManager.getLastKnownLocation(LocationManager.GPS_PROVIDER);
            mMap.clear();
            LatLng current = new LatLng(lastknownlocation.getLatitude(),lastknownlocation.getLongitude());
            mMap.addMarker(new MarkerOptions().position(current).title("Your Current location"));

        }

    }
}